JPH05249034A - Method for judging composition data of multilayered web - Google Patents

Abstract

PURPOSE: To judge the compsn. data of a multilayered web by comparing a value obtained by integrating the spectrum of a sample with a reference value to judge the form of a support and combining the integrated value of the sample and a coefficient to solve a formula. CONSTITUTION: A coefficient is judged from a sample of a multilayered web having known compsn. data. A probe spectrum of infrared rays is projected on the web of a sample to obtain the single light spectrum of the sample of the web and a probe spectrum of infrared rays is projected through air separated from the web of the sample to release to obtain the single light background spectrum. The spectrum of the sample is calculated from the single light background and the single light spectrum of the sample and corrected with respect to light dispersion effect. The spectrum of the sample corrected over a selected wave number range is integrated to limit the integrated value of the sample. The integrated value of the sample is compared with a reference integrated value to judge the system of the support in the sample. The integrated value of the sample and a coefficient are combined to solve a formula of a value of an item of a compsn. state to be judged.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to methods for obtaining compositional information. More specifically, the present invention is directed to a separate web for layered webs including hydrogen-bonded or hydrophilic layers and / or non-hydrogen-bonded or hydrophobic layers, including but not limited to photographic films or papers or supporting webs thereof. To a method for determining the water content of water.

[0002]

The measurement of moisture in moving webs, especially paper, has been the subject of several patents. Barton (B
U.S. Pat. No. 3,405,268 to Runton) and U.S. Pat. No. 3,55 to Mitchell.
1,678, Dahlin U.S. Pat. No. 3,641,349, Hill U.S. Pat. No. 3,675,019, Howarth U.S. Pat. No. 3,793,524, Howarth
rth) U.S. Pat. No. 4,006,358 and Carlson U.S. Pat. No. 4,097,743.
U.S. Pat. No. 4,345, Tamura.
See U.S. Pat. No. 4,840,706 to Campbell, No. 150. These patents measure the intensity of light transmitted or reflected through a series of optical filters that selectively transmit in the near infrared (NIR) region of the spectrum (0.8 to 2.5 micrometers). 1 illustrates a method and apparatus. One filter transmits light at a water-absorbing wavelength, commonly specified as 1.94 micrometers, while the second filter transmits light at a non-water-absorbing wavelength, typically 1.8 micrometers. Some patents further disclose the use of another filter at a wavelength where the web (eg cellulose) absorbs light, and also discloses the use of a fourth filter at a wavelength where the web does not absorb light. There is.

US Pat. No. 4,943,721 (Vidrine) describes FTIR (Fourier transform infrared).
red)) thickness gauge and beta gauge (beta g)
aug) combined use, in which the FTIR gauge is used to roughly set parameters that improve beta gauge thickness measurements. Huizinga and others use mid-infrared FTIR to monitor thin film coatings.
Are disclosed for use. GS Huzinga, E. Rudin, and E. Rudin, presented at the Joint Annual Meeting of the Analytical Chemistry and Spectroscopy Society of St. Louis, 1986. "Application of Infrared Spectroscopy to Online Monitoring of Thin Coatings" by NG Constantine (App.
license of Infrared Spec
trocopy to on-line monito
"ring of thin coatings" and GS Huzinga presented at the Pittsburgh Conference in Chicago, 1991 (JS Huzing)
a) “Comparison of near-infrared and mid-infrared spectroscopy techniques used for online quality control of moving webs (Co
mparison of Near-IR and M
id-IR Spectroscopic Techn
issues Used for On-Line Qu
aality Control of Moving W
ebs) ". U.S. Pat. No. 4,243,8
No. 82 discloses a method of measuring the thickness of a film layer by using infrared light. The method of the above patent uses several sample and reference wavelengths.

Attempts to use such a device to measure the moisture content of photographic films after drying have yielded noisy results and are generally uncorrelated with many moisture measurement techniques. During the study relating to the present invention, examination of the transmitted infrared spectrum of the web of photographic film revealed the following: That is, the very small feature associated with absorption by water in the NIR is superimposed on the very large background of light attenuation associated with light dispersion by silver halide grains in the emulsion layers of the film. This background attenuation increases at short wavelengths and is generally not reproducible either in total amount or usually in the amount of exchange with the wavenumber between films.

Background attenuation has two effects. First, the wavelengths that water and the web do not absorb have a large potential absorbance (due to the dispersion or scattering of light) compared to the additional absorbance of water or the web at the respective measurement wavelengths of water or the web. The moisture signal is very small compared to a very noisy background due to the absorbance due to the dispersion of the light. Second, the fact that the baseline varies with wavelength and the variation varies from coating to coating is not compensated for when a single reference wavelength is used for each measurement wavelength.

Yet another disadvantage of the available NIR-filtered moisture measuring devices is that only a single wavelength is used to measure moisture. If the water in the different layers of the web have exactly the same absorbance characteristics as a function of wavelength,
Then, if the measurement is done with the transmitted light,
The previously mentioned measurements are proportional to the total amount of water in the whole web. If the measurement is made with reflected or diffusely dispersed light, the measurement signal is transmitted to the web in that light is transmitted to a portion of the cross-sectional area of the web before the light is reflected or dispersed. Proportional to the total amount of water in that part of the cross section. The prior art clearly assumes that water in different layers of the web has the same absorption properties as a function of wavelength.

During the investigations related to the present invention, water placed in different chemical environments was found to have mid-infrared (2.5 to 14 micrometers) and near infrared (0.8 to 2.5 micrometers) wavelength ranges. It was found that both have different spectra. These different spectra are
The fact that the amount of light absorbed by a given amount of water at a given wavelength depends on the environment in which it is contained, especially if water is or is not hydrogen bonded to molecules in a given environment. Show how it depends.

For photographic film and paper products, a wavelength of 1.94 micrometers is more than due to hydrogen bonded water as in gelatin in the emulsion layer of photographic products.
In a hydrophobic environment (synthetic polymer support such as cellulose acetate or poly (ethylene terephthalate),
Or it is more absorbed by non-hydrogen bonded water (as in paper). These different absorptions mean that the signal measured by a single NIR filter moisture device is not just a measurement of the total amount of water or a portion of it in the entire web. At the same time, neither the desired result of the separate measurement of water in the support and water in the emulsion layer is obtained.

A further disadvantage of filtered infrared devices for the measurement of webs is that at least one measurement wavelength filter (more typically likewise a separate reference wavelength filter for each component) for each compositional component to be measured. ) Is required. In many web coating processes, there are large variations in the composition of the support and coated layers, resulting in a filter-based infrared instrument that is flexible enough to measure such varying coating process components. This is very difficult to do because the number of filters required is so large that quick feedback is not possible.

This makes it possible in all cases to obtain the entire spectrum (light intensity as a function of wavelength) and to be able to recognize product variations and to select the appropriate wavelength for analyzing the particular product being coated. There is a need for a more flexible device that provides an analytical device of choice.

Another drawback of current measurement methods relates to webs that are not completely dry. The released air (open
When obtaining the background spectrum through air), current methods generally require the moving web to be stopped and moved. Obtaining a background spectrum on a stopped web does not adequately represent free airborne components than a moving web.

In summary, the drawbacks of current filter-based NIR measurements on moving webs are (1) noisy and inaccurate measurements in the case of webs containing highly diffuse media, (2) Difficult to choose for measuring water in different chemical environments, (3) insufficient flexibility for conditions in which the components of the web change significantly in batch coating processes, and (4) ) Unable to calculate released airborne components on moving non-dried web.

[0013]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to measure the moisture content of multilayer webs, whereby a separate moisture content measurement results in hydrogen-bonded gelatin containing layers and non-hydrogen-bonded support materials. It is to provide a method performed on a layer including.

Another object of the present invention is to provide a method for more accurately measuring the moisture content of multilayer webs by increasing the moisture signal and reducing the background noise.

Yet another object of the present invention is to provide a method for determining compositional information of a multi-layer web suitable for use with multiple film formats and film support formats.

Yet another object of the present invention is to provide a method for determining compositional information of a multi-layer web, whereby each data collection step includes information of all components.

Still another object of the present invention is Fourier (Fo).
It is to provide a method for determining the compositional information of a multilayer web by using only a urier) converted infrared (FTIR) spectrometer.

Yet another object of the present invention is to provide a method for determining compositional information of a multi-layer web moving at a speed of 600 meters / minute or more.

[0019]

To achieve these and other objects of the invention, a method for determining compositional information of a multi-layer web is at least one sample of multi-layer webs having known compositional information. Determining a set of coefficients, projecting a broad spectrum of infrared radiation onto the sample web to obtain a single ray spectrum of the sample of the web, and infrared radiation through the air released away from the sample web. The steps of projecting a broad spectrum to obtain a single ray background spectrum and calculating the sample spectrum from the single ray background and the single ray spectrum of the sample, where the sample spectrum is corrected for light scattering effects. Step and modified over the selected wavenumber range And limiting the integrated value of the sample by comparing the sample's spectrum and comparing the sample's integrated value to the reference's integrated value for different support types. And the step of solving at least one formula of the value of the item of composition information to be determined by combining the integrated value of the sample with a coefficient.

[0020]

[Examples] Mid-infrared FTIR for a web whose absorbance in the measurement region is sufficiently thinner than 3.5 absorbance units larger than the baseline absorbance and is sufficiently thin and irregular so that interference fringes due to reflection from a plurality of boundary surfaces are not observed Measurement is NI
It has been discovered that no problems or increased noise are observed for coatings that are substantially more informative and moving than stationary R versus stationary coatings. These advantages are due to the considerable diffusion of emulsion layers containing silver halide.
This is especially apparent in the case of photographic film which causes e-scattering and therefore no interference fringes are observed. A common practice in spectroscopic techniques is to utilize the wavelength or wavenumber inverse in the mid-infrared region of the spectrum, but to use the wavelength in the micrometer in the near-infrared region. This convention is described here.

Before determining the compositional information of a web, called the "sample" web, a set of extinction coefficients or calibration factors is needed. The process for obtaining the extinction coefficient will be described in detail after the measuring method is described.

The next three steps in the present invention are the total infrared absorption (diffuse reflectance (dif) of the sample web.
fuse reflectance)) to obtain the spectrum. Obtaining an absorbance spectrum is the same as the through-space distance that the passages in the web have.
e) and obtaining a "single ray" background spectrum through an open channel with the same humidity or humidity. This background spectrum is usually I _o
Signal from the detector, which is the change in the intensity of the source pair number, the change in the throughput of the spectrometer pair number, the sensitivity of the detector pair and the infrared path of the through space, especially water vapor. And the amount of change in the attenuation of the signal associated with the absorbing material at. This background spectrum should be obtained as a detector gain which the manufacturer of the equipment identifies as the optimum value for the obtained signal.

Prior art methods typically obtain a single ray background spectrum by stopping and moving a moving web. It is more accurate to obtain a single ray background spectrum in the open air space in the immediate vicinity of the moving web while the web is moving at processing speed. In the case of a moist moving web, the air surrounding the web and through which the sample spectrum is obtained contains any proportion of moist constituents in the form of water vapor. When the moving web stops, the proportion of moist components in the form of water vapor in the surrounding air decreases.
When the background spectrum is obtained with the web stopped, the background spectrum does not represent the vaporized components present when the web is moving. Therefore,
The background spectrum is not an accurate measurement of the actual open air conditions surrounding the moving web. Inaccuracies in the background spectrum exist throughout the method and result in inaccurate compositional measurements.

To eliminate inaccuracies in the background spectrum, the method of the present invention takes the background spectrum in the area immediately adjacent to the moving web as it moves at processing speed. The background spectrum is obtained with the web in place and moved by sending infrared radiation through an optical fiber to the second head of the single main detector. The background spectrum thus obtained more accurately represents the composition of the open air surrounding the moving web.

The "single ray of sample" spectrum is taken through the web, but with the gain reset so that the spectrum is optimal for the resulting signal. This spectrum is commonly referred to as I _S , the “single-beam spectrum of the sample”. The "transmission" spectrum results from I _S divided by I _O at all wave numbers. Finally, the absorbance spectrum is calculated by taking the negative logarithm of the transmission spectrum.
These steps are the spectrum of the signal, namely A
(Absorbance) the wave number is reached, where the bale (Be
signal according to the concentration (C
i) and the absorption coefficient (ai) of the component at each wave number
And the sample thickness.

For the pure component case, the product of the concentration times the thickness is simply reduced to the thickness of the component, from which Beer's law states that the extinction coefficient is mg / mg, respectively.
If obtained in correct units of absorbance per absorbance or micrometer per m ^2, measured in the coated thickness of the layer, the thickness of the support in the gel laydown or moisture content or micrometer, for example in mg / m ² Give as From the above, it is clear that if the above steps are used to obtain an equation relating these to concentration and thickness, concentration analysis is done directly from the single-beam or transmission spectra of the sample. Of course, these methods are exactly equivalent to obtaining the absorbance spectra as described here. A perfectly similar set of steps arrives at a diffuse reflectance spectrum that is proportional to the product of the density times the length of the passage.

If diffuse reflectance rather than absorbance is measured, a single ray background spectrum is obtained by reflecting the projected rays away from a pure white reflector in a diffuse manner to a collection detector. The single ray spectrum of the sample is measured by reflecting the projected rays from the web and collecting the diffusely dispersed or scattered infrared. The diffuse reflectance spectrum (R) is calculated as the ratio of the diffuse reflectance from the web to the diffuse reflectance of the non-absorbing reflector. In a manner similar to the calculation of the absorbance spectrum, the modified or Kubelka-Munk diffuse reflectance spectrum is the square of 1 minus the diffuse reflectance at each wavenumber and the value is the diffuse reflectance at that wavenumber. Calculated by dividing by 2 times. The modified Beer's law is based on the relationship between the spectrum of a signal, f (r) (Kuberka-Munk diffuse reflectance versus wave number), and the concentration (C _i ) of each component.
And the intensity of that component at each wave number (turbidit
y) Expressed as being proportional to the product of the coefficient (-i) and the thickness of the sample. Although the method described here is related to absorbance, the method of measuring diffuse reflectance is equivalent.

In the fifth step of the method, the baseline absorbance is approximated by creating a straight line between the absorbances at wavenumber 2540, wavenumber 2676, wavenumber 3787, wavenumber 4536 and wavenumber 4767. At these wave numbers, no component to be measured absorbs radiation, but
The silver halide grains in the emulsion disperse light in high amounts at high wavenumbers. Since this light does not pass through the web, it has a reduced signal intensity, and thus the amount of silver halide, grain size and morphology.
It appears as an apparent absorbance that varies with and must be compensated to determine the composition of the web.
This baseline absorbance spectrum is then subtracted from the sample's absorbance spectrum to obtain a modified sample's absorbance spectrum that is only related to the absorption components of the web. The baseline correction step is illustrated in FIG. For non-photographic webs, baseline points are selected at different wavenumbers, but according to some criteria, the correction process proceeds as described.

In the sixth step of the method, the integrated absorbance value of the sample is taken to be the band of interline above the baseline described in the third step.
st) above the baseline described in two other local baseline points), which is clearly limited by the potentially broad absorbance,
In the case of photographic film obtained between the wave numbers indicated in the measurement steps described below, these wave number ranges are wave numbers 3642 to 3672 (mainly water in the support), wave numbers 3140 to 3200 (mainly water in the support). Gel and water in gel), wave number 3090 to wave number 3108 (gel, support and water in gel), wave number 3012 to wave number 3020
(Support, gel and water in gel), wave number 3940 to wave number 4110 (cellulose acetate support), and wave number 4068 to wave number 4120 (polyethylene terephthalate support), but are not limited thereto. Other wave number ranges are wave number 2850 to wave number 2858
Cyclohexane and wavenumber 306 in the support at
Plasticizer (plastic) at 0 to wave number 3080
It is used to determine the size.

In the seventh step of the method, the integrated absorbance values of the sample obtained as described above are compared with the absorbance values of the standard support format to automatically determine the support format. , And automatically determine future measurement sets or sets of extinction coefficients to be used in the sixth step. For example, if the integrated area between wave numbers 4068 and 4120 is above a certain value, the support is indicated to be polyethylene terephthalate.

In the eighth step of the method, the integrated extinction value of the sample uses Beer's law and the extinction coefficient determined in the measurement step described below for each component in each integrated wavenumber range. Combined in series or in parallel, 1) the thickness of the support in micrometers and 2) the laydown of the gel in mg /
m ² 3) the amount of water in the support in mg / m ² and 4)
The amount of water in the gel is obtained in mg / m ² . For example, Figures 2 and 3 show the water content of the support and gel as a function of relative humidity determined for equilibrated samples of film products obtained from different coating events.

In a preferred embodiment, the step of determining the modulus comprises a series of photographic film swatches, a support and a free standing gel film to which these film swatches are coated, at various relative humidities. 1 equilibration step, each of known support thickness, support type and coating gel loading. Second, the range 2000 to 600
Infrared absorbance spectra at wavenumber 0 are obtained with these films and are supported at various relative humidities. These spectra were then baseline corrected as described above in the third step of the invention and plotted as a function of humidity to show the wavenumber at which water was observed in the support and water in the gel. And bands are observed for the support and gel.

FIGS. 4, 5 and 6 show the absorbance spectra of photographic film, acetate support and independent gelatin film, respectively. The following is clear from these figures. That is, the spectral characteristics of absorbance vs. wavenumber are different for the support and for the gel, and the water in the support has a very large absorbance between wavenumbers 3500 and 3700 with a very high absorbance between wavenumbers 3200 and 3700. It has an absorbance, while the water in the gel has a very high absorbance between wave numbers 3050 and 3300 with wave number 3
It has an absorbance between 000 and 3600. From these figures it is also clear that: That is, the gel itself has a large absorbance spectrum at wavenumbers 3000 to 3600, but unlike the spectrum of water bound to the gel, the acetylcellulose support has very strong overlapping of the absorbance bands from each of the components. As a result, it has a large absorbance between wave number 2800 and wave number 3100, although it is said that no component absorbs exclusively at a given wavelength.

Examination of the spectra of photographic film (FIG. 4) shows that the four just-described components act in additional forms within the photographic film, so that the absorbance at all wavenumbers follows Beer's law. Therefore, it is considered to be an additional combination of the absorbance due to each component. Finally, FIG. 4 shows that if the absorbance becomes very high, ie about 3.0 above the baseline, the measurement will be very noisy. Therefore, compositional measurements should not be made within these spectra. For this reason, the present invention, in the preferred embodiment, is 320
Wavenumbers between 0 and 3600 are not used. However, this range can be beneficially used when analyzing thin webs. From the analysis of the spectra of many photographic films, the range irrigated in step 4 of the method of the present invention is selected as being the most informative for the analysis of composition.

Finally, the integrated absorbance value is the thickness obtained and measured in the above-mentioned spectral range,
Combined with gel loading and moisture analysis of films and substrates, a set of measurement factors equal to the extinction coefficient in Beer's law is reached, which measurement factors are well matched to the measured composition and thickness. Starting another way, the Beer equation for the individual wavenumber regions represents a series of equations, whereas the absorbance and the laydown or thickness of each component during the measuring step is known. Four or more of these equations in a given wavenumber region are solved to determine four absorbance coefficients for each component in each wavenumber region. During step 6 of the method of the present invention, for each absorbance spectrum, one has a set of four or more integrated absorbance values and associated absorbance coefficients (each absorbance range), the absorbance of which The coefficients determine the four laydown or thickness values of the sample measured in combination using Beer's law. The statistical methods for achieving these transformations are technically rich and can be either continuous or parallel in time, eg the partial least squares method.

Unique features of this measurement method include, but are not limited to, the following: 1) Water in the hydrophobic support absorbs in the 3550 to 3700 wavenumber region (although only the 3640 to 3670 wavenumber region is used in the preferred embodiment), while water, hydrogen bound to the gel, is 3000. To 3300 wavenumber region (although in the preferred embodiment the 3100 to 3300 wavenumber region is used for analysis), water and hydrophilicity bound to a hydrophobic or non-hydrogen bonded support. Or water bonded to hydrogen-bonded gelatin. The wave numbers shown are suitable for analysis and the water absorbances are both broader and overlapping than those shown above, but the supporting water is the hydrogen bound to the amide or hydroxyl, such as in gels. Absorbs at higher wave numbers than some water.

2) The wavenumber region used for this analysis is in the mid-infrared region, where A) the absorbance signal associated with all components is less than in the near-infrared region used by commercial web moisture sensors. Large and B) there is less underlying absorbance background caused by the scattering of infrared radiation by the silver halide grains in the photographic emulsion than in the near infrared. These basic phenomena have not previously been combined in order to gain the advantage of increasing the signal with less noise. This advantage is achieved because of the low background absorbance obtained with the method of the present invention.

Furthermore, the mid-infrared region provides greater separation between the wavenumbers absorbed by hydrogen-bonded water and those absorbed by non-hydrogen-bonded water than in the near-infrared region. However, the separation between the hydrogen-bonded water wave number and the non-hydrogen-bonded water wave number can also take place in the near-infrared region, and therefore hydrogen-bonded water and hydrogen-bonded water waves. Separate water near infrared measurements without water are included within the scope of the present invention.

3) The method has been developed and is commonly used for moving webs using a Fourier Transform Infrared Spectrometer (FTIR). FTIR spectrometers are available to allow greater wavelengths to provide flexibility for multi-layer film formats over multi-layer support formats (thousands in the preferred embodiment of measuring each two wavenumbers).
In that respect, it offers advantages over filter-based measurements. In addition, the automatic availability of the full spectrum of many distinct wavenumbers
Provides options for inclusion in future analyzes of compositional elements that may be significant or are added to future process changes. For example, it was possible to measure the residual solvent content of the potential support (in addition to the support thickness, gel laydown, water in the support and water in the gel).

In addition, the FTIR method obtains information from the entire spectral region during the acquisition of each data rather than the FTIR being based on the wavenumber versus time base used by the wavelength or wavenumber scanning spectrometer.
It has advantages over wavelength or wavenumber scanning full spectrum measurements.
The advantage is that the film changes over time are averaged in the FTIR method, rather than being observed as a characteristic of the spectrum in the scanning method where time correlates with wavelength or wavenumber. However, due to its drawbacks, the method of the present invention does not preclude the use of scanning spectrometers.

Obviously, there is no other successful application of FTIR alone for measuring the composition of moving webs. The FTIR method of the present invention allows the web or film product to be measured to be unpatterned and fringing.
ing) is sufficiently irregular so that it is not observed, and includes diffusely scattered layers, which is facilitated. At this point, a successful measurement is 300 m on the moving film.
It is expected that measurements up to / min and measurements up to 600 m / min and faster are possible.

4) The amount analyzed is obtained from a combination of integrated absorbance values by a standard continuous or parallel multi-component method in which the integrated absorbance is a straight line of the deposited amount or thickness of each component. It is assumed that it is a specific combination. The analysis is based on Edgar (US Pat. No. 4,885,5).
709)).

5) In the preferred embodiment based on photographic film, the measurements are taken just before the film is wound into a master roll. The water content in the wound roll has been shown to be important for photographic performance. The present invention provides a unique machine for controlling the water content in a wound roll and therefore offers unique advantages for controlling the performance of photographic films. It is in this environment of relatively low water content that the mid-infrared region of the spectrum offers particular advantages.

6) The support format can be automatically determined by analysis of selected spectral regions of the resulting transfer spectrum and different multi-component analyzes of the spectra obtained for each of these unique support formats. Can be selected automatically.

7) The method of the present invention can be used to measure the amount of water in a support, as opposed to the uncoated web of the support, as in the manufacture of the support, a photograph The amount of water in the substrate coated to form the film is measured and controlled. This control has been demonstrated in a coated photographic film because, for a given support, the amount of water in the incoming support affects the amount of water in the photographic film coated on the support. It has the unique advantage of controlling the final water content of the.

Examples Example 1 The first example illustrates typical measurement steps of a typical apparatus and method used with the present invention. In FIG. 7, an example of the apparatus used to measure the compositional information of the multilayer film is shown in the output as electrically operated mirrors 15, 17 and modified analogs with a light transmission system as shown in FIG.・ Model (AnalectModel) P
CM4000-processed FTIR spectrometer. In FIG. 7, an Analect model FX-30 interferometer 11
The light source 13 is a tungsten lamp. Interferometer 11
At its output is an electrically actuated mirror 15, which transmits infrared radiation to the potassium bromide window and about 7.62 when it travels into the path of the collimated output beam 19.
The mirror image 1 through an open passage of 3 cm
3 and deuterium substituted (deuterat
ed) triglycine sulphate (triglycine su)
lfate) Reflects on turning device 21 and provides a reference path away from the web. When the moveable mirror 15 is moved out of the infrared path, the collimated infrared light 19 from the interferometer 11 causes the collimated infrared light 19 from about 38.1 cm (15 inches) of the closed tube 23 of about 5.08 cm (2 inches) in diameter. 3 inches including a mirror 25 fixed through an inch segment, a potassium bromide window, and a multilayer web 27 to be measured.
(Inch) open path and then returned to the same turning device 21 with a similar mirror 29 and tube 31. All infrared interferograms between 800 and 6000 wavenumbers (range limited by diverting device) in either the background or the web path are of the Analect D
In the CM control computer 33, depending on the application example, 30
A data analysis computer 35, a compatible Analyst 16M, for averaging between seconds and 2 minutes and for analyzing according to the method outlined in this application.
Send to Hz 80386SX AT.

In a typical measurement step, it represents the change in support thickness from 0 to 8.5 mils and four different support formats, gel loadings between 0 and 27,000 mg / m ^2. A total of 98 samples of various photographic film products, including supports and gelatin film production runs, including about 21.
15% and 65% relative humidity at 11 ° C (70 ° F)
At each relative humidity continuously equilibrated at five different relative humidity (RH) between and, the device defined as above has a reference background single ray interferogram averaged over 2 minutes. Used to measure. The interferogram of each stationary sample was measured with the exact same 1-minute average in irregular series. The background and sample interferograms are transformed by the Fourier method into single ray spectra, which are split to obtain the sample transmission spectra, and finally they are transformed into the sample absorbance spectra between wave numbers 2000 and 6000. It The baseline spectra are obtained by drawing a straight line between the absorbances at wavenumbers 2540, 2676, 4536 and 4767, which baseline spectra are subtracted from the absorbance spectra to compensate for the light scatter by the sample. Such a baseline corrected spectrum for Film A is shown in FIG.

The integrated absorbance areas are wavenumbers 4068 to 4120, wavenumbers 3940 to 4110, and wavenumber 36.
42 to 3672, wave numbers 3140 to 3200, wave numbers 3090 to 3108, and wave numbers 3012 to 30
Calculated from these modified spectra between 20. For each of the four different support types, these areas are: support thickness, gel loading, gel moisture from the measured isotherm, support moisture from the measured isotherm. In addition, the multi-linear regression statistical module of System (Stat) is available.
Egression static module
e), analyzed by a PC-based statistical module, to obtain an average coefficient relating the measured absorbance to the measured amount. These coefficients are then used to predict the measured amount of each sample from the integrated area.
Since the actual amount of water in the gel or support is related to the thickness of the gel or support at any relative humidity, a comparison between samples is a percentage of water in the support or gel [(weight of water / area) x 100 ÷ (mass / area of support or gel)]. Examples of these percentage moisture measurements versus relative humidity are shown in FIGS. 2 and 3 for samples of two different lots of two photographic film formats.

Example 2 This example shows a comparison with a commercial near infrared moisture measurement. A sample of four films was chosen as an example of a multilayer photographic film with different amounts of silver halide grains.
The apparatus outlined in Example # 1 was used in conjunction with the method outlined therein to obtain sample absorbance spectra of these static films at six different relative humidities at about 21.1 ° C, modified for dispersion. Was used. The ratio of the intensities at wavenumbers 3012 to 3020 to the integrated intensities at wavenumbers 3642 to 3672 was fitted to the linear model of measurement vs. relative humidity to obtain the average measure of ratio vs. relative humidity. The averaging factors are amplified by individual ratios to obtain a predicted relative humidity vs. actual relative humidity plot as the square shown in FIG.

Commercially available filters Near infrared moisture sensor, Moisture System Co., Ltd.
Corp. ) From Micro quad (Micro-Q
The uad) 8000 was used to measure the same sample using the pre-determined measurement method given by the manufacturer. The result of the measurement is shown in FIG. 8 by the diamond-shaped dots. It is clear that the mid-infrared FTIR method is more precise than the methods available in this market. For a given actual relative humidity indicated by a point on the X-axis, the relative humidity predicted by the FTIR method successfully approximates the actual relative humidity more than that predicted by the microquad method.

Example 3 This example illustrates on-line measurement of a moving web. In this example, the apparatus outlined in Example # 1 was about 1.85 m (6 ft) from the point where the film was rolled into a roll at the end of the coating machine used to make the photographic film under test. Is attached at the point of. Baseline background during manufacturing operation is the 1 minute average obtained every 30 minutes. A moving web sample measurement is a continuous 30 second average. These were processed in a data analysis computer using the method determined in Example 1 and the coefficients determined in the measuring steps outlined therein to determine the thickness of the support, gel loading, moisture in the support and gel. Measure the water content inside. In FIG. 9, these outputs are plotted against time for a typical test coating. The experiment consisted of four gel coatings on a cellulose acetate support (part of the figure where the gel loading was non-zero), each with separate drying conditions with different final moisture contents. The first coating is not rigorously dried and the last one is rigorously dried over the two central coatings with similar drying conditions. Between these coatings, the instrument measured compositional information on an uncoated polyethylene terephthalate reader. This example shows that the measurement of the composition information is excellent and that there is no noise for 30 consecutive seconds, with each mark on the time axis indicating 5 minutes in that measurement.

It is understood that the present invention can be embodied in other specific forms without departing from the spirit or basic characteristics of the invention. It should be considered that the examples provided herein are for the purpose of illustrating the invention and not for limiting it. The scope of the invention is indicated by the claims,
All modifications within the scope are within the scope of the present invention.

[Brief description of drawings]

1 shows the absorbance spectrum of the sample, the baseline absorbance spectrum and the absorbance spectrum of the modified sample for film A. FIG.

FIG. 2 shows the water content of the support as a function of relative humidity for a sample of film A obtained over nine production runs.

FIG. 3 shows the water content in the gel as a function of relative humidity for a sample of film B obtained over 6 production runs.

FIG. 4 shows the absorbance spectrum of the modified sample for Film A.

FIG. 5 shows the absorbance spectrum of a modified sample on an acetate support.

FIG. 6 shows the absorbance spectra of a modified sample on an independent gelatin film.

FIG. 7 shows the shape of a typical FTIR device.

FIG. 8 shows a comparison of moisture measurement between the method of the present invention and a conventional method.

FIG. 9 shows the results of the method applied to a moving web.

[Explanation of symbols]

9 Spectrometer 11 Interferometer 13 Light source 15, 17 Mirror 19 Output light beam 21 Turning device 23 Tube 25 Fixed mirror 27 Multi-layer web 29 Mirror 31 Tube

Claims (10)

[Claims] 1. A method for determining composition information of a multi-layer web, comprising: (a) determining at least one set of coefficients from a sample multi-layer web having known composition information, each set of coefficients being Is provided with a coefficient for each item of composition information to be determined, each set of coefficients is calculated for the selected wave number range, and some selected wave number range is the number of items of composition information to be determined. And (b) projecting an infrared broad spectrum through the open air away from the sample web to obtain a background spectrum of a single ray, and (c) adding an infrared broad spectrum to the sample web. Projecting to obtain a sample single ray spectrum, and (d) Single ray background spectrum and sample single ray spectrum. Calculating the spectrum of the sample from the vector, (e) obtaining the spectrum of the modified sample by subtracting the baseline spectrum from the spectrum of the sample, and (f) integrating the spectrum of the modified sample. And an integration is performed for each selected wavenumber range used to calculate the coefficients in step (a), thereby determining the integrated value of the sample for each selected wavenumber range. , (G) comparing the integrated value of the sample with the value of the standard support type to determine the support type in the multilayer web and the corresponding set of coefficients from step (a) used in step (h). And the composition information to be determined by combining the integrated values of the sample with the set of coefficients. The method comprising the steps of: solving at least one equation for the value of the item. 2. The method of claim 1, wherein the spectrum is an absorbance spectrum and at least one equation is Beer's law equation. 3. The method of claim 1, wherein the determining step comprises determining a coefficient from a sample of a light scattering multilayer web. 4. The method of claim 1, wherein the step of projecting an infrared broad spectrum through the open air away from the web to obtain a single ray background spectrum comprises moving the multi-layer web at processing speed. During which the infrared broad spectrum is projected onto an area immediately adjacent to the moving web, thereby projecting the infrared broad spectrum through the released airborne composition moving web. A method that is substantially equal to the composition of the air above. 5. The method according to claim 1, wherein the step of obtaining the spectrum of the modified sample comprises a straight line between wave numbers that do not absorb radiation beyond the spectrum extinguished from the infrared radiation in which the component to be measured is scattered. A method comprising creating a baseline spectrum by creating. 6. The method of claim 1, wherein the straight lines are about 2540, 2676, 3787, 4536 and 476.
Method created between 7 wave numbers. 7. The method of claim 1, wherein the step of determining at least one set of coefficients comprises, at a plurality of relative humidities, a series of sample webs, a support for each of the sample webs and a sample web. Equilibrate independent gelatin gels for each step of each of the swatch webs, the steps at which the support and gelatin film are of known thickness, format and gel loading, and relative humidity, respectively. Projecting a broad spectrum of infrared light onto each of the webs, the support and the gelatin film to obtain a single-beam spectrum of the sample; The steps of projecting a wide spectrum of infrared rays into a single ray background spectrum, Calculating a sample spectrum from the line spectrum and a single ray background spectrum; obtaining a modified spectrum of each of the sample web, the support and the gelatin film by subtracting the baseline spectrum from the sample spectrum; Plotting a modified spectrum for each of the relative humidity of the sample, selecting a wavenumber range from the plotted and modified spectrum sensitive to the item of compositional information to be determined, and selecting the selected wavenumber range. Integrating the modified spectrum to determine the integrated value of the sample for each selected wavenumber range, and the integrated value of the sample to the known thickness, format and coated gel. Combined with the amount deposited, a set of coefficients for each selected wavenumber range The method comprising the steps of: solving a set of equations to be. 8. The method of claim 7, wherein the step of selecting a wavenumber range is such that the modified value is above baseline.
A method comprising selecting a wavenumber range from a portion of the spectrum that is not greater than 5 units. 9. The method of claim 8 wherein the step of selecting a wavenumber range comprises about 3642 to 3672.
3140 to 3200, 3012 to 3020, 3
940 to 4110, 4068 to 4120, 28
A method comprising selecting at least one wavenumber range of 50-2858 and 3060-3080. 10. The method of claim 4, wherein the items of compositional information to be determined by solving at least one equation are support thickness, gel laydown, amount of water in the support and A method involving the amount of water in the gel.